In a pen & paper roleplaying game usually the players play their characters, and the DM plays the rest of the world. "The world" sounds like a huge job, but frequently it isn't: The world is really a huge blank slate, which springs in existence only where observed by the players. And there it is often spontaneously populated by a jumble of generic fantasy tropes. Your group is looking for a blacksmith? Sure! He's a dwarf, loves gold, and speaks with a Scottish accent. The world can be generic because it is only the backdrop of an adventure which most of the time could play in just about any fantasy world.

The Zeitgeist campaign I just started is very different. Basically there is a campaign story and the whole world has been designed around that campaign story. It is a one-shot world, it only serves this one campaign and isn't designed as a backdrop for different campaigns or collections of adventures. On the one side that is great, because it is a lot more interesting than those fantasy tropes. On the other side it means that this time playing the world actually *is* a huge job. I had to read and re-read hundreds of pages of campaign guides and adventures to understand how the world is operating and what is going on in order for me to tell that to the players.

Now, after the first adventure has properly started and we already had a rather epic battle aboard an exploding steamship, I am starting to become comfortable with that job of playing the world. The world is starting to come alive in my head. While thinking about the start of the next session I was able to turn half a phrase of text from the adventure into an idea of a short scene that fits perfectly into this world and gives the players a real choice of actions with predictable consequences. I've completely prepared the first adventure, already read the second adventure once and started preparing stuff for that, and generally am feeling up to the task. I just hope that this all translates into a great experience for my players as well, as this campaign is asking more role-playing of them than previous ones.

While not totally on topic this post makes me wonder if this translates to video games.

The gaming industry has been in an "open world" boom for a few years now. The worlds in some of these games function a lot like the generic campaign that you mentioned here. They are simply backdrops or excuses for the player's actions/gameplay. I would drop something like Skyrim or Destiny into this category.

A few of these open world games are more like the Zeitgeist campaign. They have more intricate worlds. Things happen in the world that do not depend on the player at all. Stories advance and the player is simply a part of the world instead of having center stage. An example of this would be something like the Witcher 3.

Both categories can have excellent games. Both can draw millions of players. Which is better? It's all subjective.